This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Activatable contrast agents (ACAs) for magnetic resonance imaging (MRI) allow for time-resolved visualization of physiological events in vivo. The information gained from such images can provide insight into the metabolic processes associated with a number of diseases and could potentially aid in their diagnosis. However, the synthesis of gadolinium-based ACAs is long and complex, and their efficacy is highly sensitive to minute structural changes. This project aims to develop and evaluate computational techniques for the prediction of optimal target structures for ACAs using the Zn(II)-activated Gd-daa-n series as a model system. Specifically, we intend to use a combination of density functional theory (DFT) and molecular dynamics to explore the conformational changes which occur upon ion binding and how these changes affect the relaxation properties of the molecules.